package com.flqy.baselibrary.widget.transform;

/**
 * Copyright (C) 2015 Wasabeef
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.ColorMatrix;
import android.graphics.ColorMatrixColorFilter;
import android.graphics.Paint;
import androidx.annotation.NonNull;

import com.bumptech.glide.Glide;
import com.bumptech.glide.load.engine.bitmap_recycle.BitmapPool;
import com.bumptech.glide.load.resource.bitmap.BitmapTransformation;

import java.security.MessageDigest;

public class GrayscaleTransformation extends BitmapTransformation {

	private BitmapPool mBitmapPool;

	public GrayscaleTransformation(Context context) {
		this(Glide.get(context).getBitmapPool());
	}

	public GrayscaleTransformation(BitmapPool pool) {
		mBitmapPool = pool;
	}

	@Override
	protected Bitmap transform(@NonNull BitmapPool pool, @NonNull Bitmap toTransform, int outWidth, int outHeight) {
		Bitmap source = toTransform;

		int width = source.getWidth();
		int height = source.getHeight();

		Bitmap.Config config = source.getConfig() != null ? source.getConfig() : Bitmap.Config.ARGB_8888;
		Bitmap bitmap = mBitmapPool.get(width, height, config);
		if (bitmap == null) {
			bitmap = Bitmap.createBitmap(width, height, config);
		}

		Canvas canvas = new Canvas(bitmap);
		ColorMatrix saturation = new ColorMatrix();
		saturation.setSaturation(0f);
		Paint paint = new Paint();
		paint.setColorFilter(new ColorMatrixColorFilter(saturation));
		canvas.drawBitmap(source, 0, 0, paint);
		return source;
	}


	public String getId() {
		return "GrayscaleTransformation()";
	}

	@Override
	public void updateDiskCacheKey(@NonNull MessageDigest messageDigest) {
		messageDigest.update(getId().getBytes(CHARSET));
	}

}
